Implementing a turbo-demodulation scheme is complex, especially when an iterative channel decoder is used in the turbo-demodulation scheme.
When a powerful iterative channel decoder is used, for example using a LDPC code, a convolutional turbo-code (CTC) or a block turbo-code (BTC), the decoders of these codes have in common to work according to the turbo principle. Internally some units, either implemented in hardware or software, exchange information in an iterative way.